PROJECT SUMMARY Patients treated with dialysis report very low levels of physical activity, and physical activity correlates with functional status, which is also impaired in the dialysis population. In the general population, higher levels of physical activity are associated with lower cardiovascular risk and better endothelial function. There are recommended levels of physical activity for the general population that are known to improve both cardiovascular risk and endothelial function. Although there are international guidelines for physical activity in patients treated with dialysis, the activity targets (which are derived from evidence in non-dialysis populations) are not being met. Prior exercise studies in the dialysis population have focused on aerobic training or resistance training and have shown improvement in physical functioning, but very few studies have actually targeted increasing physical activity. The moderate to vigorous interventions studied may limit participation for many dialysis patients. The major goal of this study is to determine whether a pedometer-based intervention can increase physical activity among patients on dialysis and whether increasing activity can improve physical and endothelial function, and symptom severity. We propose a 3-month randomized controlled trial comparing pedometers and weekly activity goals to usual care among 60 patients on dialysis, with a 6 month-follow up for maintenance. Our research approach and study design allow for measurement of change over time not only in the intervention group but in the standard of care group, in an area for which little longitudinal data exists. Our study could establish an important and actionable link between exercise, endothelial function, and cardiovascular health in this complicated population.